IgG1 subclass restriction of oligoclonal IgG from cerebrospinal fluids and brain extracts in patients with multiple sclerosis and subacute encephalitides.

Oligoclonal-IgG-containing cerebrospinal fluids (CSF) from patients with multiple sclerosis and subacute encephalitides were studied for IgG subclass distribution by immunoelectrophoretic and hemagglutination inhibition methods. The immunoelectrophoretic results indicated the presence of electrophoretically restricted IgG1 proteins in a number of CSF, compatible with an association between this IgG subclass and oligoclonal IgG proteins. The combined results indicated a greater dominance of IgG1 over other IgG subclass proteins in CSF than in matching sera. Similar results were obtained in experiments with brain extracts from patients with subacute sclerosing panencephalitis. The results differed from those obtained with normal CSF, where the distribution of IgG subclasses resembled that of the matching sera. It is concluded that the oligoclonal IgG of the CSF and brain in the patients studied belong mainly to the IgG1 subclass.